Random notes in no particular order:
9 Expertise is going to put a serious, serious damper on your Threat. I consider 15 a "minimum" and I'm sure you know 26 is necessary to remove Dodges. Look for more Expertise, even if that means gemming for it.
Use the 32 Stamina/2% Armor meta gem. It's an all-around superior tank gem. Do what you must to make up for the lost Defense (your shield and chest enchants can easily be swapped to compensate).
Stop gemming for Parry. 8 Parry/12 Stamina gems should be replaced with 8 Expertise/12 Stamina, 16 Expertise or 24 Stamina depending on socket color, bonus and meta gem needs. Your belt, for instance - I would go 16 Defense/24 Stamina not your strange mix of Dodge, Parry and Defense.
No offense, but Alchemy/Herbalism? If you're really serious about tanking, you need at least ONE of Blacksmithing, Mining or Jewelcrafting. Preferably a combination of these: Blacksmithing/Mining or Blacksmithing/Jewelcrafting is what I would reccommend personally. Expensive, I know - but important if you really want to excel.